Modern gas turbines, in particular aircraft engines, must meet the highest demands with regard to reliability, weight, performance, cost-effectiveness, and service life. In particular in civil aviation, aircraft engines have been developed over the previous decades which fully meet the above-mentioned requirements and have reached a high degree of technological perfection. Among other things, material selection, the search for new, suitable materials, and the search for new manufacturing methods play a decisive role in the development of aircraft engines.
The most important materials used today for aircraft engines or other gas turbines are titanium alloys, nickel alloys (also known as super alloys), and high-strength steels. High-strength steels are used for shaft components, gear components, compressor housings, and turbine housings. Titanium alloys are typical materials for compressor components. Nickel alloys are suitable for the hot components of the aircraft engine.
Precision casting and forging are primarily known from the related art as manufacturing methods for gas turbine components made of titanium alloys, nickel alloys, or other alloys. All highly stressed gas turbine components such as blades for a compressor are forged components. In contrast, rotating blades and guide blades of the turbine are as a rule designed as precision cast components.
For reducing the weight of gas turbine components it is known from the related art to use metal matrix composite materials (known as MMC materials). High-strength fibers are embedded in the metal material of such MMC materials. However, the manufacture of gas turbine components using such MMC materials is expensive. Moreover, rotating blades of a gas turbine rotor, for example, cannot be manufactured using such MMC materials, since rotating blades made of MMC materials have only limited strength vis-à-vis bird strike, for example.
Another approach for reducing weight known from the related art is to design gas turbine components as hollow components. Blades are already manufactured as hollow blades with the aid of diffusion welding. However, such diffusion-welded hollow blades are expensive.